Protecting water quality
Water Quality Assurance Program
Residents of the City of Toronto and York Region can have complete assurance in the safety of the drinking water.
The City of Toronto's four water treatment plants have highly effective water treatment and quality assurance processes in place. This ensures that the water is free of harmful chemicals and that E.coli and other disease-causing bacteria are not present in tap water.
The treatment processes are based on a multiple barriers concept whereby coagulation, filtration and chlorine disinfection perform complimentary roles in physically removing and inactivating disease causing organisms which might be present.
These processes are monitored by continuous analyzers, which provide an immediate confirmation of process effectiveness.
Back-up systems are in place to insure that equipment malfunctions are immediately remedied in order to provide seamless treatment.
Regular sampling and analysis:
Toronto's drinking water comes from Lake Ontario through intake pipes that are one to three kilometres away from shore and at a depth of 15 metres. This configuration minimizes the potential for onshore events such as heavy rainfall adversely affecting finished water quality.
The city's water production unit samples the treated drinking water at each operating plant every four hours to confirm the absence of bacteria. The city's Water Quality Unit conducts more than 50,000 bacteriological tests at the filtration plants every year to monitor incoming and process water quality, as well as the finished product. Additionally, approximately 20,000 bacteriological tests are performed on water samples collected from the distribution system to ensure that degradation does not occur following treatment.
We analyse a comprehensive list of potential chemical contaminants. Overall, the list of substances tested for exceeds 300. This exceeds the 78 chemicals for which health based standards exist in Ontario.
The City's main drinking water laboratory is formally accredited for performing compliance tests on drinking water.
Toronto's drinking water always meets or exceeds the Ministry of the Environment's Ontario Drinking Water Standards. The city has established its own water-quality objectives for specific parameters that are more stringent than the provincial objectives. Daily reports on the bacteriological analysis from each plant are sent to the Ministry of Environment (MOE) as well as the Public Health Division.
The Region of York has its own Quality Assurance Program that samples water within the region's distribution system used for Toronto supplied water. Wells are also used as a water supply source in the Region of York.
In Toronto, approximately 50 residents have water supplied from private wells. The city recommends that these individuals have their water supply analyzed regularly by a qualified laboratory.
Toronto Medical Officer of Health informed of irregularities:
In case of a finding of adverse water quality the results are immediately forwarded to Toronto's Medical Officer of Health as well as the MOE for notification of the public if necessary. Should it be determined that water as supplied to the Region of York was also adversely affected, the Medical Officer of Health for the Region would also be notified.
If an irregularity is detected further analysis of the site and the distribution area around the site is undertaken. The area of concern would be immediately isolated should corrective measures be deemed necessary. In consultation with the Medical Officer of Health, city staff would determine appropriate measures to be taken to restore water quality.
Plants operate under provincial regulation:
The city's water treatment plants operate in compliance with the Ontario Safe Drinking Water Act and its associated Regulations as well as MOE certificates of approval (C. of A.). Operators are well trained and certified by the MOE. Ministry inspectors inspect Toronto's plants regularly to ensure compliance.
Publication of test results:
Test results on the quality of Toronto's water are available to the public. Summary reports are available on the web site and hard copies are available at Access Toronto desks or can be mailed to interested residents. Individual test results are also available upon request.